<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		/*#p1{
			font-size: 30px;
			color: green;
		}
		#p2{
			color: green;
			text-decoration: underline;
		}
		#p3{
			font-size: 30px;
			text-decoration: underline;
		}*/

		.lg{
			font-size: 30px;
		}
		.lv{
			color: green;
		}
		.un{
			text-decoration: underline;
		}

	</style>
</head>
<body>
	<!-- 
		张孕康1 30px green
		张孕康2 green text-decoration:underline;
		张孕康3	30px 下划线
	 -->
	 <!-- 公共类 -->
	 <p id="p1" class="lg lv">张孕康1</p>
	 <p id="p2" class="lv un">张孕康2</p>
	 <p id="p3" class="lg un">张孕康3</p>

	
</body>
</html>